1. Field
The present invention generally relates to techniques for designing chassis and disk carriers for accommodating hard disk drives (HDDs) in computer systems. More specifically, the present invention relates to a method and an apparatus for rapidly designing and assessing chassis and HDD carriers based on vibration-resilience characteristics of HDDs.
2. Related Art
Computer systems such as servers and storage arrays can be adversely affected by mechanical vibrations of internal components and structures. These vibration problems are becoming more significant because of the following trends: (1) cooling fans are becoming increasingly more powerful; (2) chassis and support structures are becoming weaker because of design modifications to reduce cost and weight; and (3) internal disk drives, interconnects, and other system components are becoming increasingly more susceptible to vibration-induced failures. For example, hard disk drives (HDDs) are becoming more susceptible to vibrations because the storage density for HDDs has increased to the point where a write head has to align with a track which is less than 20 nanometers wide. Moreover, the write head floats only 7 nanometers above the disk surface. These extremely small dimensions make the read and write performance of the HDDs very sensitive to vibrations.
Characterizing the response of components in a computer system, such as HDDs, to vibrations generated by the computer system can be important in both designing computer systems and diagnosing problems in computer systems. Some HDD vendors have chosen to mitigate vibrations in HDDs through vibration damping or by providing passive/active compensation for vibration-induced errors inside HDDs. Unfortunately, these compensation mechanisms only work effectively in certain vibration frequency ranges defined by the cost of the compensation logic and quality of embedded accelerometers. This makes it extremely difficult to select the most suitable HDDs based solely on the vibration specifications provided by the vendors. Moreover, although such vibration specifications may guarantee no hard errors on a disk drive, vibrations may cause the read and write throughput performance of the disk drive to be significantly degraded.